hard to learn
Французский не так трудно выучить, как некоторые думают.
French isn’t as difficult to learn as some people think.
Русский очень трудно выучить.
Russian is very difficult to learn.
Греческий трудно выучить.
Greek is difficult to learn.
Русский язык трудно выучить.
Russian is a difficult language to learn.